System for diminishing the load of platform which traces the location of moving objects and method thereof

ABSTRACT

In existing moving object tracking, there is a great communication load between a terminal and a platform, because the terminal should report its location to the platform every second or every minute and the platform should frequently process the location form the terminal. It is possible to reduce the great communication load on the server, by calculating an error between the current GPS location and the estimated location at a specific time on the basis of the estimated arrival time of the moving object. It allows that the terminal report its location to the server only when the error between current GPS location and the estimated location is greater than a predetermined threshold value.

TECHNICAL FIELD

The present invention relates to a system and a method for reducing acommunication load of a platform for tracking a moving object, and moreparticularly, to a system and a method for reducing a communication loadof a tracking platform in which an estimated arrival time for a movingobject to move from a current location to an arrival location(destination) is calculated and then a communication path between themoving object to be tracked and the tracking platform is disconnectedwhen the calculation of the estimated arrival time is completed.

BACKGROUND ART

There are known three tracking methods. In the first method, a terminalof a moving object reports an own location to a tracking server(hereinafter, referred to as “tracking platform” or “platform”) atconstant time intervals. In the second method, the platform requests theterminal to send the location of the moving object. In the third method,when road network data is available, the terminal reports the locationof the moving object to the platform based on road segment informationonly if road segments are changed.

In the first method, the terminal reports its location to the platformevery second or every minute and the platform processes data on thereported location. Accordingly, an excessive overloading ofcommunication data load between the terminal and the platform can becaused. Therefore, the first method is not suitable for urgent caseswith the need for urgency and accuracy.

In the second method, when the time interval at which the platformacquires the location of the terminal decreases, the platform requeststhe location of the terminal more frequently, and the terminal has tocollect, calculate, and report the location information in response tothe request. Accordingly, the excessive overloading of communicationdata load between the terminal and the platform may be caused as thefirst method. In addition, the platform needs to track the location ofthe terminal in real time, which is not supported by the second method.

In the third method, the terminal has to report the location of theterminal to the platform every road segment. In this method, thefrequency of reporting the location is less than that of the first orsecond method and the platform can track the terminal in real time.However, if the road network is consisted of a number of small roadsegments, the communication load between the terminal and the platformmay be increased as the first and second methods. The reason is, as thenumber of road segments increases, the number of issuing updates alsoincreases.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a system according to an exemplary embodiment of thepresent invention.

FIG. 2 is a flowchart of a method according to an exemplary embodimentof the present invention.

FIG. 3 shows an example of the present invention in relation to a path(road).

BRIEF SUMMARY OF THE INVENTION Technical Goal of the Invention Problem

The present invention provides a system and a method for reducing acommunication load of a platform for tracking a moving object byreducing the frequency of communications for reporting a location of aterminal of the moving object.

Disclosure of the Invention Technical Solution

A moving object occupant (a terminal user) inputs a current location andan arrival location of the moving object by the use of a terminal havinga location detection module and reports the current location and thearrival location to a platform. The platform searches a geographicinformation database (DB) for location information on the currentlocation and the arrival location, extracts all the possible paths, andcalculates an estimated arrival time. The platform transmits theextracted paths and the estimated arrival time to the moving object(terminal).

The terminal calculates a difference in distance between the currentlocation and an estimated location of the moving object detected in realtime by the location estimation module built in the moving object on thebasis of all the possible paths, the estimated arrival time, and thecurrent location information of the moving object detected in real timeby the location detection module. At this time, the current location ofthe moving object is reported only when the difference in distance isgreater than a predetermined threshold value.

Advantageous Effect of the Invention

According to the present invention, it is possible to drastically reducethe frequency of communication between the terminal and the server andcommunication load on the server. The reason is that location updatefrom terminal to server is happened only if predefined threshold isexceed at predefined location at a specific time, on the basis of theestimated arrival time of the moving object.

In addition, according to the present invention, it is possible for theserver to estimate the location of the moving object by the use of alocation estimation algorithm, without any additional communicationbetween the terminal and server. Therefore, when location based serviceproviders request the server for the location of the moving object, theserver can provide the location of the moving object in real time on thebasis of the estimation data without any additional communication withthe terminal.

DETAILED DESCRIPTION OF THE INVENTION

According to an aspect of the present invention, there is a providedsystem for reducing a communication load of a platform for tracking amoving object, the system including: an estimated arrival timecalculating unit receiving a current location and an arrival location ofthe moving object from the moving object, calculating estimated arrivaltime for the moving object to reach the arrival location, andtransmitting the estimated arrival time to the moving object; a terminalwhich is located in the moving object, receiving the estimated arrivaltime and determining an estimated location; and a communication pathon-off controlling unit inactivating a communication path for reportingthe current location and the arrival location from the moving objectwhen the terminal receives the estimated arrival time is received, andactivating the communication path when the estimated arrival time has tobe newly calculated again.

According to an aspect of the present invention, there is provided amethod of reducing a communication load of a platform for tracking amoving object, the method including: (a) receiving a current locationand an arrival location of the moving object, calculating an estimatedarrival time for the moving object to reach the arrival location, andtransmitting the estimated arrival time to the moving object; (b)transmitting the estimated arrival time to a terminal of the movingobject and allowing the terminal, which is located in the moving object,to determine an estimated location of the moving object; and (c)inactivating a communication path for reporting the current location andthe arrival location from the moving object when the terminal receivesthe estimated arrival time. In addition, the method may further include(d) activating the communication path when the estimated arrival timehas to be newly calculated again.

Mode for Invention Embodiments

Hereinafter, the present invention will be described in detail byexplaining exemplary embodiments of the invention with reference to theattached drawings. Like reference numerals in the drawings denote likeelements.

FIG. 1 shows an exemplary embodiment of a system according to thepresent invention and FIG. 2 shows an embodiment of a method accordingto the present invention.

A location-tracking platform 11 corresponds to the aforementionedplatform. The location-tracking platform 11 extracts paths between thecurrent location and the arrival location of a moving object 10 byreceiving the current location and the arrival location from theterminal 101. Then the location-tracking platform 11 calculates theestimated arrival time to move from an arbitrary location on theextracted path to the arrival location.

For this, the location-tracking platform 11 includes a path generationrequesting unit 111, a path extracting unit 112 and an estimated arrivaltime calculating unit 113. When a current location and an arrivallocation of a moving object 10 are reported from a terminal 101 locatedin a moving object 10 (S201), all the possible paths between the currentlocation and the arrival location are extracted on the basis of thereported current location and arrival location and the estimated arrivaltime is calculated and transmitted to the terminal 101 (S202).Alternatively, the location-tracking platform 11 further includes amoving object location estimating unit 114 with a real-time locationestimation algorithm and estimates the location of the moving object 10.The estimated arrival time is calculated based on the estimatedlocation.

Hereinafter, a function of tracking the moving object 10 performed bythe path generation requesting unit 111, the path extracting unit 112,the estimated arrival time calculating unit 113, and the moving objectlocation estimating unit 114, will be described in detail. The pathgeneration requesting unit 111 receives the current location and thearrival location from the terminal 101 located in the moving object 10,makes a request message for generating paths between both locations andtransmits the request message to the path extracting unit 112.

The path extracting unit 112 receives the request message from the pathgeneration requesting unit 111, accesses to a geographic database (DB),extracts all the possible paths between both locations, and transmitsthe extracted paths to the estimated arrival time calculating unit 113.

The estimated arrival time calculating unit 113 calculates the estimatedarrival time to move from the arbitrary location to the arrival locationof the moving object 10 with reference to the extracted paths and anestimated location of the moving object 10 estimated by the movingobject location estimating unit 114 in real time and then transmits thecalculation result together with the extracted path information to theterminal 101.

An exemplary embodiment of the present invention will be described indetail with reference to FIGS. 1 and 2.

The location-tracking platform 11 receives the current location and thearrival location from the terminal 101 located in the moving object 10through the reporting path and transmits the current location and thearrival location to the path generation requesting unit 111. Thereporting paths a and b will be described clearly in the following. Theterminal 101 includes an own current location detecting unit 1101detecting the current location (real location) of the moving object 10in real time, and the terminal user inputs the current location detectedby the current location detecting unit 1101 and the arrival location ofthe terminal user through the terminal 101 and then transmits the inputsto the location-tracking platform 11.

The path generation requesting unit 111 makes the request message forgenerating paths including information on the current location andarrival location and transmits the request message to the pathextracting unit 112. When the path extracting unit 112 extracts all thepossible paths between both locations from the geographic DB (S2021),the path extracting unit 112 converts the information on the currentlocation and arrival location into coordinate data, transmits theconverted data to the path information DB, receives the information onall the possible paths between the current location and the arrivallocation, and extracts the paths between both locations.

The estimated arrival time calculating unit 113 receives all thepossible paths extracted by the path extracting unit 112, accesses to areal-time traffic condition providing server 12, and receives currenttraffic conditions. In addition, the estimated arrival time calculatingunit 113 refers to the estimated location of the moving object 10estimated by the moving object location estimating unit 114 in realtime, calculates the estimated arrival time for the moving object 10 toreach the arrival location from an arbitrary location, and transmits thecalculation result together with the extracted path information to theterminal 101 (S2202).

At this time, an estimated location determining unit 1012 built in theterminal 101 located in the mobile object 10 and the moving objectlocation estimating unit 114 estimates the location of the moving object10 interactively. Specifically, the estimated location determining unit1012 estimates a location of the moving object 10 at an arbitrarylocation based on all the possible paths to the arrival locationreceived from the location-tracking platform 11, the estimated arrivaltime, and the current location of the terminal 101 detected by thecurrent location detecting unit 1101 in real time.

When all the possible paths to the arrival location, the estimatedarrival time, and so on are transmitted to the terminal 101, acommunication path on-off controlling unit 13 inactivates the reportingpaths a and b as a normal neutral state (the state at which both pathsare not activated). The communication path on-off controlling unit 13will be described more clearly in the following.

A distance difference measuring unit 1013 compares the current locationdetected by the current location detecting unit 1011 in real time withthe estimated location detected by the estimated location determiningunit 1012 in real time and measures the difference in distance betweenthe current location and the estimated location in real time (S204).

When the difference in distance between the current location and theestimated location is greater than the predetermined threshold value,the distance difference measuring unit 1013 makes the communication pathon-off controlling unit 13 activate the communication path (reportingpath) b for reporting that the difference in distance is greater thanthe threshold value (S205). The distance difference measuring unit 1013reports the current location through the reporting path b to thelocation tracking platform 11 when the difference in distance betweenthe current location and the estimated location is greater than thepredetermined threshold value (S206).

The path from the new current location received from the distancedifference measuring unit 1013 to the arrival location are newlyextracted, and the estimated arrival time is newly calculated (S207) andtransmitted to the terminal 101, by the function modules of the trackingplatform 11 as described above. After being transmitted to the terminal101, the aforementioned operations are performed as described above(S208). The terminal 101 and the location tracking platform 11 estimatesand tracks the location of the moving object 10 continuously by the useof the location estimation algorithm on the basis of the new path andestimated arrival time in real time until the moving object 10 reachesthe arrival location.

The communication path on-off controlling unit 13 is used for activatingone of the reporting communication paths a and b and is included so asto reduce the communication load.

That is, the communication path on-off controlling unit 13 activates thereporting path a when a terminal user reports the current location andthe arrival location to the location tracking platform 11 through theterminal 101. The communication path on-off controlling unit 13activates the reporting path b when the difference in distance isgreater than the predetermined threshold value. The communication pathon-off controlling unit 13 inactivates both reporting paths a and b inthe other cases. Therefore, communication path on-off controlling unit13 can suppress unnecessary communications between the terminal 101 andthe location tracking platform 11.

When the extraction of the path and the calculation of the estimatedarrival time are requested from the communication path on-off controller13, that is, the aforementioned report is requested, the communicationpath on-off controlling unit 13 detects the report event and holds thecommunication state for reporting the current location and the arrivallocation from the terminal 101 to the location tracking platform 11 toreduce the communication load. The report event according to anembodiment of the present invention occurs only when the user inputs thecurrent location and the arrival location and requests the trackinglocation platform 11 to track the moving object or the difference indistance is greater than the predetermined threshold value, or so thelocation tracking platform 11 has to calculate the estimated arrivaltime.

FIG. 3 shows an example according to the present invention in relationto a path (road).

For example, when the moving object 10 having the terminal 101 desiresto move from a predetermined starting location to the arrival location,the terminal 101 detects the current location through the currentlocation detecting unit 1011 and transmits the detection result togetherwith current speed information to the tracking platform 11, and the pathextracting unit 112 in the location tracking platform 11 accesses to thegeographic DB and extracts all the possible paths between the startinglocation and the arrival location.

In a case where the terminal 101 reports the current location of themoving object 10 to the location tracking platform 11 and the locationof the terminal 101 is estimated only when the segment is changed basedon the road segment (A->B->C->D->E) information, that is, in case of theaforementioned third method, though the moving object 10 does notdeviates from the range of the threshold value, the difference indistance between the current location and the estimated location of themoving object 10 is smaller than the predetermined threshold value, thecurrent location of the moving object 10 has to be reported to theserver whenever the segment is changed.

However, according to the method of the present invention, the reportevent occurs only when the difference in distance between the currentlocation at a predetermined time and the estimated location at thepredetermined time is greater than the threshold value (thresholddistance) regardless of the road configuration. Accordingly, when thedifference in distance is not greater than the threshold value, thelocation tracking platform 11 estimates the location of the movingobject 10 in real time without additional location reports, ininteraction with the estimated location determining unit 1012.Therefore, the present invention has the great advantage to reduce thecommunication load, specifically when the number of the segmentsconstituting the road is large.

The invention can also be embodied as computer readable codes on acomputer readable recording medium. The computer readable recordingmedium is any data storage device that can store data which can bethereafter read by a computer system.

Examples of the computer readable recording medium include read-onlymemory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes,floppy disks, optical data storage devices, and carrier waves (such asdata transmission through the Internet). The computer readable recordingmedium can also be distributed over network coupled computer systems sothat the computer readable code is stored and executed in a distributedfashion.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the spirit and scope of theinvention as defined by the appended claims.

The exemplary embodiments should be considered in descriptive sense onlyand not for purposes of limitation. Therefore, the scope of theinvention is defined not by the detailed description of the inventionbut by the appended claims, and all differences within the scope will beconstrued as being included in the present invention.

1. A system for reducing a communication load of a platform for trackinga moving object, the system comprising: an arrival time prediction unitreceiving a current location and an arrival location of the movingobject from the moving object, calculating estimated necessary time forthe moving object to reach the arrival location, and transmitting theestimated necessary time to the moving object; a terminal which islocated in the moving object, receiving the estimated necessary time anddetermining an estimated location; and a communication path on-offcontrolling unit inactivating a communication path for reporting thecurrent location and the arrival location from the moving object whenthe terminal receives the estimated necessary time, and activating thecommunication path when the estimated necessary time has to be newlycalculated again.
 2. The system of claim 1, further comprising: a pathgeneration requesting unit receiving the current location and thearrival location and making a request message for generating a pathbetween the current location and the arrival location; a path extractingunit receiving the request message and extracting all the possible pathsbetween the current location and the arrival location; and a movingobject location estimating unit estimating the estimated location of themoving object in interaction with the terminal, wherein the estimatednecessary time calculating unit calculates the estimated necessary timebased on the extracted paths and the estimated location.
 3. The systemof claim 2, wherein the terminal comprises: a current location detectingunit detecting the current location of the moving object in real time;an estimated location determining unit determining the estimatedlocation of the moving object in real time when the moving object islocated at the current location on the basis of the detected currentlocation, the extracted paths and the estimated necessary time; and adistance difference measuring unit measuring a difference in distancebetween the current location and the estimated location in real time anddetermining in real time whether the difference in distance is greaterthan a predetermined threshold value.
 4. The system of claim 3, whereinthe communication path on-off controlling unit activates thecommunication path, only when the moving object reports the currentlocation and the arrival location to the platform arbitrarily or thedifference in distance between the current location and the estimatedlocation is greater than the threshold value.
 5. The system of claim 4,wherein, when the difference in distance is greater than the thresholdvalue, the distance difference measuring unit reports the currentlocation to the platform, and the platform extracts new paths betweenthe current location and the arrival location, calculates a newestimated necessary time, and transmits the new estimated necessary timeto the terminal.
 6. A method of reducing a communication load of aplatform for tracking a moving object, the method comprising: (a)receiving a current location and an arrival location of the movingobject, calculating an estimated necessary time for the moving object toreach the arrival location, and transmitting the estimated necessarytime to the moving object; (b) transmitting the estimated necessary timeto a terminal of the moving object and allowing the terminal, which islocated in the moving object, to determine an estimated location of themoving object; and (c) inactivating a communication path through whichthe moving object reports the current location and the arrival locationto the platform when the terminal receives the estimated necessary time.7. The method of claim 6, further comprising: (d) activating thecommunication path when the estimated necessary time has to be newlycalculated again.
 8. The method of claim 7, further comprising: (e)allowing the terminal to detect the current location of the movingobject in real time; (f) determining the estimated location of themoving object at the time corresponding to the detected current locationon the basis of the detected current location, the extracted paths, andthe estimated necessary time; (g) measuring a difference in distancebetween the current location and the estimated location in real time anddetermining whether the difference in distance is greater than apredetermined threshold value in real time; (h) reporting the currentlocation to the platform when the difference in distance is greater thanthe threshold value; and (i) allowing the platform to extract new pathsto the arrival location based on the reported current location, tocalculate a new estimated necessary time, and to transmit the newestimated necessary time to the terminal.
 9. The method system of claim8, wherein the communication path is activated only when the movingobject reports the current location and the arrival location to theplatform arbitrarily or when the difference in distance between thecurrent location and the estimated location is greater than thethreshold value.